Scientists expected the opposite, but polar bears in the Norwegian Arctic archipelago of Svalbard have become fatter and healthier since the early 1990s, all while sea ice has steadily declined due to climate change.
Polar bears rely on sea ice as a platform from which to hunt the seals that they rely on for blubber-rich meals. The bears' fat reserves provide energy and insulation and allow mothers to produce rich milk for cubs.
Researchers weighed and measured 770 adults in Svalbard between 1992 and 2019 and found that bears had become significantly fatter. They believe that Svalbard bears have adapted to recent ice loss by eating more land-based prey, including reindeer and walruses.
The discovery, published in Scientific Reports, was particularly puzzling because of the impact of climate change in Svalbard. During the same period that this research was carried out, global temperature rise has reduced the number of ice-free days per year in the region by almost 100, at a rate of about four days each year.
The fatter a bear is the better it is, explained lead researcher Dr. Jon Aars from the Norwegian Polar Institute. And I would have expected to see a decline in body condition when the loss of sea ice has been so profound.
Walruses have been officially protected in Norway since the 1950s, after they were hunted to near extinction. This protection has boosted their numbers, providing a new source of fatty food for polar bears. There are a lot more walruses around [for them to hunt] these days, said Aars.
He also explained that, if seals have smaller areas of sea ice available to them, they will congregate in those smaller areas, presenting easier pickings for bears.
While this is unexpectedly good news for these Arctic predators, the researchers think it is unlikely to last. As the sea ice continues to decline, bears will have to travel further to access hunting grounds, using more energy and depleting precious fat reserves.
Experts think the new findings could be linked to the population recovering from heavy hunting pressures until protections were introduced in the 1970s, along with an increase in the number of walruses and reindeer in recent decades providing the bears with a temporary boost.
Dr. John Whiteman, chief research scientist at Polar Bears International, indicated that although this news is positive in the short term, the long-term picture for polar bears remains grim if ice loss continues unchecked. He emphasized that these bears need sea ice to survive and cautioned that if global warming advances, populations could face serious declines.
Polar bears rely on sea ice as a platform from which to hunt the seals that they rely on for blubber-rich meals. The bears' fat reserves provide energy and insulation and allow mothers to produce rich milk for cubs.
Researchers weighed and measured 770 adults in Svalbard between 1992 and 2019 and found that bears had become significantly fatter. They believe that Svalbard bears have adapted to recent ice loss by eating more land-based prey, including reindeer and walruses.
The discovery, published in Scientific Reports, was particularly puzzling because of the impact of climate change in Svalbard. During the same period that this research was carried out, global temperature rise has reduced the number of ice-free days per year in the region by almost 100, at a rate of about four days each year.
The fatter a bear is the better it is, explained lead researcher Dr. Jon Aars from the Norwegian Polar Institute. And I would have expected to see a decline in body condition when the loss of sea ice has been so profound.
Walruses have been officially protected in Norway since the 1950s, after they were hunted to near extinction. This protection has boosted their numbers, providing a new source of fatty food for polar bears. There are a lot more walruses around [for them to hunt] these days, said Aars.
He also explained that, if seals have smaller areas of sea ice available to them, they will congregate in those smaller areas, presenting easier pickings for bears.
While this is unexpectedly good news for these Arctic predators, the researchers think it is unlikely to last. As the sea ice continues to decline, bears will have to travel further to access hunting grounds, using more energy and depleting precious fat reserves.
Experts think the new findings could be linked to the population recovering from heavy hunting pressures until protections were introduced in the 1970s, along with an increase in the number of walruses and reindeer in recent decades providing the bears with a temporary boost.
Dr. John Whiteman, chief research scientist at Polar Bears International, indicated that although this news is positive in the short term, the long-term picture for polar bears remains grim if ice loss continues unchecked. He emphasized that these bears need sea ice to survive and cautioned that if global warming advances, populations could face serious declines.
